For new off-grid housing sites, rural developers want a fuel that is cost-effective and hassle-free to install. Liquefied petroleum gas (LPG) continues to be a popular choice for many rural developers, but for those new to the fuel, what does the installation process involve and what aspects do developers need to consider? During this year’s Rural Housing Week – taking place 2nd – 6th July – Ian Digby, Specification Manager at Calor, discusses in more detail.
LPG can be installed as a communal system, creating the closest alternative to mains gas for rural sites, with the gas stored centrally underground and distributed through a network of pipes. Not only does this improve the overall aesthetic of the estate, it makes refuelling and maintenance easier as it can all be managed in a single, central location.
Many developers are keen on LPG for an off-grid housing development, as the ability to install a full gas central heating system in the property is seen as a strong selling point to potential buyers, who are used to its familiarity, reliability and comfort.
Initial discussions will involve identifying a suitable location and determining the number of LPG tanks required. Many housebuilders believe a significant number of tanks are required to service a development, and a large plot of land will be needed to accommodate these. However, due to the continued improvements in the energy efficiency of new houses, a typical 25 home development can now be comfortably supplied from two 4,000-litre tanks, requiring a site no larger than 9 metres by 7 metres.
Underground LPG tanks should be located at least 3.4 metres away from buildings and boundaries, measured from the centre point of the lid on the tank. Consideration must also be given to how the tanks will be accessed by a refuelling tanker, which will need to be parked within 30 metres of the tanks. Ideally, the land above the tanks should be grassed or gravel-finished, for easy maintenance and to protect the aesthetics of the site. This area will often be finished with a discrete knee rail fence to show the boundary of where the tanks are sited.
The groundworks are relatively straight-forward. A single excavation is required to accommodate the tanks underground, with a concrete base to ensure a safe and stable foundation. Then, once the LPG tanks have been fitted, the installation of pipework and meters follow the same regulations as mains gas. Pipework will typically be medium-density polyethylene, and should be dug into a trench with a depth of 750mm, with a 250mm distance from other utilities.
Investing in LPG
Other off-grid fuels, such as oil, electric heating and air source heat pumps (ASHPs), are significantly more expensive for developers to install in terms of the cost of the equipment and the installation process itself. In contrast, LPG combination boilers are the same size and have the same flue clearance as standard gas boilers – allowing the developer to follow standard house design layouts and reducing overall build costs. Regardless of the size of the property, selecting ASHPs will require an internal layout redesign to accommodate a cylinder cupboard and associated hot water storage. For optimum performance, underfloor heating should be specified as well. This adds unnecessary expense for developers, particularly on smaller two and three-bedroom properties.
Due to the lower CO 2 emissions of LPG, fewer energy-saving measures – such as solar PV or mechanical ventilation heat recovery – are needed when compared with alternative off-grid fuels too. Low-cost ‘bolt ons’, such as waste water heat recovery or hi-therm lintels, can help an LPG installation meet the desired SAP ratings (Part L1A Building Regulation Compliance) if needed.
Ultimately, LPG offers developers the closest alternative to mains gas and significantly lower build costs than many other fuel options, making it the ideal fuel of choice for off-grid developments.